Anti-D from alloimmunization versus RhIG: detective work in the blood bank and transfusion medicine services

The blood bank and transfusion medicine services (BBTMS) engages with electronic health records (EHRs), clinicians, and outside hospitals (OHs) to obtain comprehensive patient history to optimize care. Detection of anti-D in a pregnant patient underscores this work. Differentiating passive anti-D due to RhIG administration versus alloanti-D affects clinical decision making. The objectives of this study were to identify the required steps, barriers, and outcomes of anti-D investigations in obstetric patients.

This retrospective case series reviewed nine pregnant patients over 24 months, for whom anti-D was identified with no reported RhIG history. Six steps were performed to ascertain anti-D history: 1) review the on-site EHR; 2) contact the on-site obstetrician, 3) review history from the automatic health information exchange (HIE) with OHs using the same EHR platform, 4) request information from OHs with a shared EHR platform and without automatic HIE, 5) contact the OH BBTMS, and 6) communicate with the outside ambulatory practice (OAP).

The investigations revealed that eight of nine patients received RhIG before their presentation. Five patients received RhIG at an OH's emergency department and three at an OAP. One patient's history remained unknown after initial investigations; however, a subsequent sample unveiled a confounding alloantibody.

In the absence of a national HIE, continuity of care suffers through omission of critical information. Strategies to avoid confusing passive anti-D and alloanti-D include expanding HIE capabilities and use of patient identification cards with critical BBTMS information to include RhIG administration dates.